Process for breaking petroleum emulsions



Patented Sept. 7, 1943 PROCESS FOR BREAKING PETROLEUM EMULSIONS Gwynne Allen, Long Beach, Calif., assignor to Petrolite Corporation, Ltd., St. Louis, Mo., a corporation of Delaware No Drawing. Application May 27, 1942 Serial No. 444,762

This invention relates primarily to the treatment of emulsions of mineral oil and water, such as petroleum emulsions, for the p rpose of separating the oil from the water.

This invention is a continuation in part of my copending application, Serial No. 392.099, filed on May 6, 1941. Reference is also made to my copending applications Serial Nos. 444,761, 444,763, 444,764, 444,765, 444,766 and 444,767, filed May 27. 1942.

One object of my invention is to provide a novel process for resolving petroleum emulsions of the water-in-oil type. that are commonly referred to as cut oil, "roily oil," emulsified oil, etc, and

which comprise fine droplets of naturally-occur ring waters or brines dispersed in a more orless permanent state throughout the oil which constitutes the continuous phase of the emulsion, my process being particularly adapted to the resolution of crude oil emulsions of the kind obtained in connection with the treatment or the flooding of subterranean oil-bearing strata by means of aqueous agents or the like.

Another object of my invention is to provide an economical and rapid process for separating.

emulsions which have been prepared under con-' trolled conditions frbm mineral oil,'s'uch as crude petroleum and relatively soft waters or weak brines. Controlled emulsification and subsequent demulslfication under the conditions just men'-' tioned are of significant value in removing impurities, particularly inorganic salts, from pipeline oil.

The process which constitutes one feature of my present invention consists in subjecting a petroleum emulsion of the water-in-oil type to the action of a demulsifyins agent, thereby causing the emulsion to break and separate into itscomponent parts of oil and water or brine when the emulsion is permitted to remain in a quiescent state, after treatment, or is subjected to other equivalent separatory procedure. The demulsifying agent employed in my process consists of an. aminated polymeric sub-rubbery sulfur-con.- verted ester of a polyhydric alcohol, and more particularly an ester in which there are present at least 2 acyl radicals derived from unsaturated hish molal' monocarboxylic detergent-forming acids having at least 8, and not more than 32, carbon atoms each.

It is known that when elemental sulfur is heated with a reactive detergent-forming carboxylic acid, for example with oleic acid,'the sulfur adds at' the double bond in the oleic acid chainorradical. Wheretheoleicacidlsemployed in combination with a polyhydric alcohol, such as glycerol, as for ..examp1e in triolein which is the triglyceride of oleic acid, the reaction apparently does not stop with the formation of a simple addition product. Instead, as discussed in'the literature. e. 8.. Knight and Stamberger. J. p

Chem. Soc. London, 1928, pp. 2791-8, triolein takes up additional sulfur atoms, possibly'even tied in through the glyceryl. radical. Also, it isprobable that the several fatty acid radicals present are also linked through sulfur atoms. Compare comparablereactions involving more reactive sulfur dichloride, and particularly the formation of cyclic bisulfides. Such reactions indicate the rationale for thioglycerol formation, or, more ex- 'actly, the formation of sulfurized esters of mmglycerol. See Chemistry of Synthetic Resins." Ellis, 1935, volume 2, 1176-77. At any rate, in the course of the reaction, polymers begin to be formed and a certain degree of elasticity becomes apparent. Molecular weight determinations show the presence of polymers-including diads and triads (dimers, trimers), etc. Destruction of the polymeric body, for example by saponification r with, alkali, results in a reduction of the molecular, weight, loss of the elastic properties, and

"apparently a return to ashnpler addition product. In my process, I make no claim to the use of the simple unpolymerized addition product of.

sulfur and an unsaturated high molal monocarboxylic detergent-forming acid having at least 8, and not more than 32, carbon atoms, typified by sulmrized oleic acid. Imake no claim to the use of the. free detergentsforming carboxylic acid and sulfur alone in preparing my reagents; but

Iemploy the acid only in combination with a polyhydric alcohol compound containingtwo or more alcoholiform hydroxyl groups, in the form of an ester of such acid and such polyhydric alcohol. I

The compound containing the two or more alcoholiiorm hydroxyl groups may be a simple polyhydric alcohol, such for example as glycerol or ethylene glycol, or it may. be a condensed polyhydric alcohol like polyglycerol, diethylene glycol, iii-glycerol, or tri-sLVcerol. .In addition to the above polyhydric alcohols, I'may also use mannitan, sorbitan, pentaerythrltol, and dipentaerythritol. I may use ether alcohols so long as they have two or more hydroxyl groups in the molecule, 1. e. (polyhydric alcohols in which a v carbon atom 'chain is interrupted at least one by oxygen, as exemplified by diethylene'. glycol previously mentioned). They are allcharacteriaed by containing two or more alcoholiform hydroxyl indicated by very simple tests.

Ikind exemplified by groups and by having the power to form esters with an unsaturated high molal monocarboxylic detergent-forming acid having at least 8, and not more than 32, carbonatoms.

Resinous and imilar materials are sometimes classified as thermoplastic, thermo-setting," and element-convertible." The expression element-convertible refers particularly to plastic coatings or drying oils in which hardening apparently is due to conversion into a new compound or composition by action of an element used, often oxygen. Thus, drying oils are often referred to as being oxygen-convertible. For practical purposes, the only other element finding wide application for this purpose is sulfur. Hence certain products, and particularly certain oils, are referred to as sulfur-convertible,"

meaningthat they react with sulfur or sulfur r di-chloride to get polymeric materials, rubbery masses, factice, or the like. V

The unsaturated high molal detergent-forming monocarboxylic acids employed by me in preparing my reagent are characterized by having a carbon atom chain, which I shall denote as R," containing at least 8 carbon atoms and not more than 32 carbon atoms, and which must contain at least one unsaturated bond, 1. e., at least one ethylene linkage. Such acids are sometimes referred to as ethylenic."

The acyl radical may, of course, have present other non-functional groups, suchas hydroxyl groups, acyl-oxy groups, etc. It is .only necessary that the presence of such groups does not detract from (a) the detergent-forming ability of the acids, and (17) their susceptibility to sulfur conversion. Suitability of substituted acids is For instance, saponification with caustic potash, caustic soda, or the like, must yield a soap or soap-like material. Secondly, if the detergent-forming properties have not been eliminated by the presence of this substituent atom or radical, then it is only necessary to determine that susceptibility to sulfur conversion is still present. Such test is obviously the same procedure as is herein described for preparing my reagent, except tbat it is conducted on a mall scale in the laboratory. If the substituted acid or ester, which has been previously determined to have detergent-forming properties, also shows sulfur conversion susceptibility, it is, of course, equivalent of the with equal or even greater effectiveness. 7

,Such high molal acids may be obtained from various sources, such as ofls, fats, and waxes;. or one may use petroleum acids, rosin acids, and the like. Petroleum acids include naturally-occurring naphthenic acids and also acids obtained by the oxidation of hydrocarbons and waxes. Rosin acids include abietic acid, pyroabietie acids, and the like. Saturated acids, such as saturated fatty acids, saturated naphthenic' acids, saturated oxidized petroleum acids, etc., can frequently be converted into an unsaturated acid by halogenization,-followed by a reaction of the the internal Wurtz reaction.

. My preference is to use unsaturated fatty acids, due, to their low ,ost and ready availability. One need not use a single fatty acid but may use i the mixture obtained by saponiflcation of a naturally-ioccurringoil or fat. For

reference is made to the our naturally in olive oil, castor oil,

fatty acids, which ocpeanut oil,

cottonseed oil, fish oils, corn oil. soybean oil, linseed oil, sesame oil, lard oil, oleo oil, perilla oil, and many other naturally-occurring oils. Rapeseed oil, for example, contains appreciable proportions of tri-erucin, the trl-glyceride of erucic acid. I have found it'useful to prepare my reagent.

As has been previously pointed out, the high molal acids are used in the form of the polyhydric alcohol ester having at least 2 such high molal acid radicals present. Since it is my preference to use the naturally-occurring fatty acids, itobviously follows that my preference is to use the naturally-occurring glycerides. However, if desired, one can obtain the high molal acids from any source and esterify such acids with various polyhyclric alcohols, such as the glycols, in the conventional manner to produce suitable esters, which may or may not have a free or unreacted alcoholiform hydroxyl group present. The fatty acid di-glycerides typify these esters which contain a free or ,unreacted alcoholiform hydroxyl group (in the residue of the polyhydric alcohol, glycerol). The fatty acid tri-glycerides do not possess this free alcoholiform hydroxyl. Both types of 'glyceride, for example, are suitable for my purpose, provided the fatty acid present satisfies the above-expressedrequirements; The manufacture of such esters is so well known that no description is required in the present instance. v

One may select esters of the mixed typ and such mixed esters may even contain acyl radicals which either are not high molal in character or are not unsaturated, i. e., ethylenic in nature. For instance, diolein may be reacted with one mol of acetic acid or one mol of stearic acid to give an ester which would be satisfactory for the present purpose. As an example of a modified ester which may serve, reference is made to triacetylated triricinolein.

I have found that, in addition to naturallyoccurring fatty acids,'in addition and substitution products of fatty acids obtained by' the action of chemical reagents on fatty acids-which latter modified fatty acids bear a simple genetic I relationship to the parent fatty acids from which the obviuos functional unsubstituted or unmodified acids or esters herein described, and may be used they were derived-are also useful for making my reagent so long as they are in part unsaturated, i. e., possess some double bond, as shown by possession of an iodine number of appreciable magnitude.

Instead of employing natural poly esters of reactive detergent-forming carboxylic acids in preparing myrea'gent, I may use synthetic esters obtained by esterifying one or more reactivedetergent-forming carboxylic acids with a polyhydric alcohol of the kind heretofore recited and described in a conventional esteriflcation reaction, such as reacting the alcohol with the acid or acids in various molecular proportions in the presence of,'for example, dry hydrogen chloride.

The compound produced by the interaction of a polyhydrlc alcohol of. the above kind and a reactive detergent-forming carboxylic acid of the above kind will be termed afpoly ester in instance, special the presenfdscription. In all instances. it must contain two or more radicals or residues derived from reactive detergent-forming carboxylic acids, which may be the same orxdifierent acids; and itkcontains one or more radicals or residues derived from polyhydric alcohols.-

Diglycerides of unsaturated fatty acids are examplesof poly esters, just as'are the naturallyoccurring tri-glycerldes of unsaturated fatty acids.

The reaction of elemental sulfur with such a.

when the reaction is allowed to proceed at controlled temperatures, there is obtained a complex polymeric sulfurized product of high molecular weight, which is semi-elastic and highly viscous, and which approaches the consistency of rubber, depending on the time and temperature of reaction and the proportions of reactants employed.

The nature of the chemical changes which take place is, to the best of my knowledge, not yet fully understood. I have referred above to a literature reference which suggests various mechanisms for the polymerization process. Without attempting to express exactly the composition of the reagents I empley, I desire to use those polymeric sulfurized bodies, obtained as above recited, which have a consistency short of rubber. Accordingly, I have termed. them sub-rubbery to denote a range of polymerization between the simple sulfur addition products, on one hand, and the non-usable rubbers produced on super-polymerization, on the other. Such sub-rubbery products are capable of dissolving in solvents to produce fluid reagents which are practicable to be used commercially.

After preparing the polymeric sub-rubbery sulfurized derivative of a poly ester of a reactive detergent-forming carboxylic' acid, as above recited, I then aminate said derivative by means of an amino-body of the following kind:

obvious monomers, such as amine salts, which are not condensates.

In preparing my preferred reagent, 125 parts by weight of castor oil are heated to 180 C. teen parts by weight of sulfur are added, and the mixture is stirred continuously for 45 to 60 minutes at 188 to 190 C., or until a sample withdrawn from the reaction vessel and cooled is semi-elastic and transparent, indicating the complete absence of unreacted sulfur. To this sulfurized body there is then added parts by weight of triethanolamine. The temperature is reduced somewhatby'such addition, but is still sufficiently high to produce the desired reaction between the sulfurized castor oil body and the tri-ethanol-' amine.

Asa second example of a reagent which I prefer to use, the following is given; 298 parts of ricin- The class of alkanolamines for my purpose is characterized by the presence, in the molecule, of one or more alkanol or substituted alkanol groups, i. e., groups like CH2OH, -C2H4OH, C3HsOH, etc. They also contain one or more amino nitrogen atoms in the molecule. The commonest examples of the class are tri-ethanolamine, di-ethanolamine, and monoethanolamine; but the class also includes, for example, ethylethanolamine, di-propanolamine, tri-propanolamine, benzylethanolamine, cyclohexylpropanolamine, etc. In every case, the molecule of the alkanolamine contains one or more alkoxy or aralkoxy groups of the above kinds. One may also have amines of the same general type in which one or more simple alkanol groups is replaced by a related group containing an ether linkage. For example, the alkanol group in the ethanolamines is C2H40H. Amines containing, for example, the ether-linked group ester of -(a) a' reactive detergent-forming carboxylic acid, and (b) a polyhydric alcohol with an alkanolamine of the above-described kind, to produce a complex condensation product. Such product may be properly referred to as a condensate within the commonly used meaning of such term, and thus differentiate from certain oleic acid are mixed with 46 parts by weight of glycerol, and the mixture is agitated and heated in the presence of dry hydrogen chloride gas at a temperature in excess of C. for a period of time sufiicient to produce an ester. (1 have found that reacting -6 hours at C. is satisfactory to accomplish this.) If this procedure is tedious of undesirable, the di-glyceride of ricincleic acid may be prepared in any other desired manner. For example, di-glycerides are commonly prepared by treating two mols of thetri-glyceride with one mol of glycerol in the presence of an alkaline catalyst. The ester so produced is mixed with 15% of its weight of elemental sulfur,'and the agitation and heating are continued until all the sulfur is assimilated and a clear t ansparent product is obtained, as shown by a test on glass. The product has considerable viscosity and a semi-elastic nature. This product is then mixed with 53 parts by weight of di-ethanolamine at the same temperature, 150 C., and agitation is continued for a period of time until the react-ion is complete. Usually, heating may b discontinued on addition of the di-ethanolamine, the reaction being completed by the time the temperature'has dropped to atmospheric levels.

Other esters of unsaturated fatty acids or other reactive detergent-forming carboxylic acids of the kind heretofore mentioned may be used instead of the castor oil andthe ricinoleic acid. For example, I have used cottonseed oil instead of castor oil in making certain examples of my reagent, and have found it to be useful therein. However, when cottonseed oil is used the reaction is usually not-as smooth as when castor oil is employed. Also, itis usually found that longer heating is required to produce the desired reagent of optimum properties. It is, therefore,.preferable to use castor oil rather than cottonseed oiL-sb far as I am now aware-.. Also, other alkanolamines may be used instead of the tri-ethanolamine and di-ethanolamine of the above examples.

The stages of polymerization and cond tion and the elastic properties of the resulting products may be altered by varying the temperature of the reaction, the time of the reaction, or the proportions of reactants employed, 'or any combinationof these variables. I have foimd that the most effective reagents are those obtained by reacting 100 parts by weight of the ester with from 10 to 17 parts by weight of sul-. fur, controlling the temperature to avoid the evolution of hydrogen sulfide so far as is practicable, and employing a time suflicient to attain highly polymerized products which are, how-. ever, still soluble in petrolemn distillates; and

Fif

then aminating such trlethanolamine using approximately parts by weight of the amine.

While the foregoing description has shown products obtained by subjecting a sulfurized poly ester to the action of an amino-body, I have also found that the procedure may be modified in that the amination of the poly ester may take place first; and the aminated poly ester may be subsequently sulfurized to produce highly useful products. My invention, therefore, goes equally to the use of polymeric sub-rubbery derivatives produced by sulfurizing aminated poly esters of (a) reactive detergent-forming carboxyli acids, and (b) polyhydric alcohols. The final products are broadly similar, but not necessarily of identical structural configuration when amination takes place before sulfurization and when amination takes place after sulfurization of the poly ester. In-other words, I have also found that it is possible to prepare a reagent of broadly similar composition and of equally valuable properties by varying the above-recited method of preparation as follows: Instead of aminating a sulfurized poly ester of a detergent-forming carboxylic acid and a polyhydric alcohol, as above recited, I have reacted, for example, the same proportions of castor oil and tri-ethanole amine, and have subsequently added the same proportion of sulfur with heat and stirring to produce my reagent. This alternative procedure usually offers no material advantages over that recited hereinbefore. In some instances, it appears to have adisadvantage in that black specks appear in the mixture in the course of manufacture (which, however, usually disappear on prolonged stirring under heat). I, therefore, prefer to employ the procedure recited above as to preferred reagents. However, my invention contemplates the use of a reagent produced either by aminating a sulfurized poly ester of the abovedescribed type or sulfurizing an aminated poly ester of the above-described type. The products sulfurized bodies with to 20 .so produced are ordinarily somewhat basic in character. To the extent that basicity existsin the product, it-=may be'used in its original form, or it may be neutralized wholly or in part by reaction with a suitable acid. I have found, for example, that the acetates and the iactats prepared by reacting such basic examples of my product with acetic or lactic acid frequently have notable merit. My invention is intended to include the use of such salts, therefore.

The complex aminated polymeric sub-rubbery sulfurized compound obtained as recited above may be diluted with one or more solvents or diluents to improve its viscosity or other characteristics, as desired. Examples of suitable diluents are isopropanol, mineral spirits, benzol, etc.

In practising my process, the improved treating agent hereinbefore described is usually employed in the proportion of one part of reagent to from 2,000 to 20,000 parts of petroleum emulsion, either in concentrated form or after diluting as desired with a suitable vehicle or diluent or solvent. I desire to point out that the superiority of my reagent or demulsifying agent is based on its ability to treat or break certain emulsions more advantageously and at a lower cost than is possible with other available demulsifiers or conventional mixtures thereof.

In practising my process, a reagent of the kind I above described is brought into contact with or is caused to act upon the emulsion to be treated. in any of the various ways or by any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used either alone or in combination with some other demulsifying procedure, such as the electrical dehydration process.

While I have described in detail the preferred embodiment ,of my invention, it is understood that the materials employed, the proportions of ingredients, the arrangements of steps, and the details of procedure may be variously modified without departing from the spirit of the subjoined claims.

As has been pointed out, alkalnolamines include those compounds in which the hydroxylated radical linked to the nitrogen atom may contain a carbon atom chain, which is interrupted by an oxygen atom, as well as the conventional type, in which there is no interruption in the carbon atom chain. Reference to a basic alkanolamine radical in the hereto appended claims is employed in this broad sense. The propriety of such broader aspect is obw'ous, in light of the functional equivalence previously indicated.

I claim:

1. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsiflercomprising an amino sub-rubbery polymeric sulfur-converted polyhydric alcohol condensate ester; said ester prior to sulfur-conversion containing at least 2 unsaturated high molal detergent-forming monocarboxylic acid radicals having at' least 8 carbon atoms and not more than 32 carbon atoms each; said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is free from a nitrogen-linked aryl radical.

' 2. A process for breaking petroleum emulsions of the water-in-oiltyp characterized by subjecting the emulsion to the action of a demulsifler comprising an amino sub-rubbery polymeric sulfur-converted polyhydric alcohol condensate ester; said ester prior to su1fur-conversion containing at least 2 unsaturated high molai'detergent-forming monocarboxylic acid radicals having at least 8 carbon atoms and not more than 32 carbon atoms each; and said ester prior to sulfur-conversion being free from any unreacted hydroxyl radical as part of the alcoholic residue; said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is free from a nitrogenelinked aryl radical.

3. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifler comprising an'amino sub-rubbery polymeric sulfur-converted polyhydric alcohol condensate ester; said esterv prior to sulfur-conversion containing at least 2 unsaturated fatty acid radicals having at least 8 carbon atoms and not more than 32 carbon atoms each; and said ester prior to sulfur-conversion being free from any unreacted hydroxyl radical as part of the alcoholic residue; said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is free from a nitrogen-linked aryl radical.

4. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifler comprising an amino sub-rubbery polymeric sulfur-converted polyhydric alcohol condensate ester; said ester prior to sulfur-conversion conconversion being free from any unreacted. hydroxyl radical as part of the alcoholic residue, said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is taining at least 2 monoethylenic fatty acid radicals having at least 8 carbon atoms and not more than 32 carbon atoms each; and said ester prior to sulfur-conversion being free from any unreacted hydroxyl radical as part of the alcoholic residue; said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is free from a nitrogen-linked aryl radical.

5. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subject ing the emulsion to the action of a demulsifler comprising an amino sub-rubbery polymeric sulfur-converted polyhydric alcohol condensate ester; said ester prior to sulfur-conversion containing at least 2 radicals derived from mono ethylenic fatty acids having 18 carbon atoms each; and said ester prior to sulfur-conversion being free from any unreacted hydroxyl radical as part of the alcoholic residue; said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is free from a nitrogenlinked aryl radical.

6. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifler comprising an amino sub-rubbery polymeric sulfur-converted glycerol condensate ester; said ester prior to sulfur-conversion containing 3 monoethylenic fatty acid radicals having 18 carbon atoms each; and said ester prior to sulfurfree from a nitrogen-linked aryl radical.

7. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising an amino sub-rubbery polymeric sulfur-converted tri-ricinolein; said amino radical being a basic alkanolamine radical, in which the amino nitrogen atom is free from a nitrogenlinked aryl radical.

8. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a .demulsifier comprising a tri-ethanolamine-rea'cted subrubbery polymeric sulfur-converted polyhydric alcohol condensate ester; said ester prior to sulfur-conversion containing at least 2 unsaturated high molal detergent-forming monocarboxylic acid radicals having at least 8 carbon atoms and not more than 32 carbon atoms each.

9. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a tri-ethanolamine-reacted subrubbery polymeric sulfur-converted tri-ricinolein.

GWYNNE ALLEN. 

